“Fifty-one’s all his now,” said Butler. “Fourteen-year vet? What are you gonna say? No???”

Butler, an obviously intelligent young man, said yes. Happily. Respectfully.

Coming to the Chargers this season as a free agent, Spikes is a two-time All-Pro linebacker who’s already had the kind of lengthy career and vast experience that Butler desires. And when it came time for Butler to choose a new jersey number, he basically used the same selection strategy that National Football League teams are always citing at draft time.

“I chose the best number available,” said Butler. “I know there might be some heh because of the last person who wore it, but you know, I’m ready. I’m wearing it.”

The number is 56. Uh huh.

There is a somewhat unpleasant coincidence to the fact that Butler, the inside linebacker from Washington whom the Chargers made a special point of drafting in 2010, now is adorned with the same numeral worn by Shawne Merriman in San Diego until this year.

Butler already is putting it to good use, however. Though essentially a rookie, he's quickly established himself as a special teams player and one of the Chargers' most promising options at inside linebacker, playing right next to Spikes on a majority of snaps The Chargers could still sign a veteran linebacker, but that decision may depend on the play of Butler, who's already impressed the coaching staff with his instincts.

"We've just got to make sure we're smart with what he does," said head coach Norv Turner. He added: "The No. 1 thing is, he's holding up. That's a hard injury to come back from."

That is, the Achilles, the same sort of injury that kept Merriman on the sidelines last season and ultimately prompted the Chargers to cut him loose in November. If you didn’t know at the top of this story that Butler’s number last year was 51, it’s because an Achilles injury suffered in training camp cost him the entirety of his debut season.

“I was here,” said Butler, who arrived in San Diego with his bachelors degree in construction management. “Every day.”

About this time a year ago, Butler was charging on a pass-rush drill against running backs. He went to plant his left foot, which suddenly went numb on him. The tendon had snapped. You could tell then that Butler wouldn’t be back soon.

“It was very difficult,” he said. “As a rookie, I had high hopes of helping on special teams, then making it on the defense. For that to go down, it was just demoralizing. It’s life, and you’ve got to live with it, but there was a good two-, three-week period where I was out of it, for sure.”

The Chargers were feeling his pain, too. General manager A.J. Smith had made his high opinion of Butler -- a 6-foot-1, 245-pounder from the University of Washington whose strength numbers were the best of any linebacker at the NFL Combine -- quite evident. To get him, Smith had arranged a trade with the San Francisco 49ers to move up 12 places in the third round.

As a reminder of Butler’s lost season of 2010, Smith put a magnet with Butler’s name back on the board in the third round of the Chargers' draft class of 2011. The gesture was symbolic in more ways than one.

In effect, because he was injured almost before his professional career began, Butler is starting all over again on the practice field. He has the benefit of a year in the Chargers system, privy to the film sessions and game plans and the guidance of veterans, but he’s also coming off almost 11 months in the recovery process.

"I'm back to making plays," Butler said Monday. "I got my confidence back, my swag(ger). I'm more accustomed to the system, the checks, the plays."

Butler is in an interesting place at a particularly interesting time. The Chargers are in a major transitional phase at both linebacker – no longer with the team are defensive captain Stephen Cooper, Kevin Burnett, Antwan Applewhite and Brandon Siler, not to mention Merriman – and special teams. The first-round pick of 2010, Larry English, is likewise on the mend from offseason surgery.

They have a new defensive coordinator in Greg Manusky, which might have something to do with the arrivals of Spikes and fellow linebacker Travis LaBoy, both of whom were coached by Manusky with the 49ers. All the more reason for Butler to pick Spikes’ brain.

“I’m already learning from him,” said Butler. “He’s always interjecting words of wisdom. He’s played both inside linebacker spots in our defense. I’m staying in his back pocket."